Electrical discharge device and method of making the same



June 27, 1944. 2,352,522

7 ELECTRICAL DISCHARGE DEVICE AND METHOD OF MAKING THE SAME w. w. ElT EL ETAL I 2 Sheets-Sheet 1 Filed Feb. 14, 1941 INVENTOR5 WILL/HM w- 511-51.

' BY JACK A "CULLOUEH THE/E ATTORNEY IIIII June 27, 1944. W E.T L Em 2,352,522

ELECTRICAL DISCHARGE DEVICE AND METHOD OF MAKING THE SAME Filed Feb. 14, 1941 I 2 Sheets-Sheet 2 I'i 5 fig .5

INVENTOR5 WILL/AM W EITEL THE/E ATTORNEY JACK A- cuLLouaH amfzaw Patented June 27, 1944 UNITED STATE ELECTRICAL DISCHARGE DEVICE AND METHOD OF MAKING THE SAME William W. Eitel and Jack A. McCullough, San Bruno, Calif., assignors to Eitel-McCullough,

Inc., San Bruno, Calif.

fornia a corporation of Cali Application February 14, 1941, Serial No. 378,900

9 Claims.

Our invention relates to electron discharge devices; and more particularly to thermionic tubes.

It is among the objects of our invention to provide an improved multiple-unit tube wherein several operative units are assembled within a single envelope, and in. which the individual units are designed with electrode spacings approximately the ideal in regard to transit time effects, electron migration, interelectrode capacity, and thermionic efliciency.

Another object is to provide a tube of the character described having a plurality of units adapted for operation either singly or simultaneously.

Another object is to provide a multiple-unit tube in which a unit may be brought into operation after another unit is disabled, thus increasing the life of the tube; and in which an inactive unit may be employed for neutralizingcapacity Still another object is to provideimproved means for connecting like electrodes of the units in parallel for simultaneous operation.

A further object i to provide improvements in the anode structure of an electron discharg device, which improvements may be-embodied in an ordinary single-unit tube as well as in our mu1- tiple unit tube.

A still furtherobject is-toprovide an improved method-of assembling tubes to simplify their fabrication and insure alignment and accurate spacing of; the electrodes. 7 f Theinvention possesses other objects and'features of advantage, some of which, with the foregoing; will be set forth in the following description of'our invention; It is to be understood that we do not limit ourselves to this disclosure of species of our invention, as we may adopt variant embodiments thereof, within the scope of the claims.

Referring to the drawings:

Figure 1 is a side view, partly in section and partly in elevation, showing a twounit tube embodying the improvements of our invention; and Figure 2 is an-exploded view of the same illustrating the electrodes mounted on the several envelope sections. v

Figure 3 is a fragmentary view showin a modified construction in which the anodes are unitarily supported; and V Figure 4 is a horizontal sectional view taken in a plane indicated by line 44 of FigureB,

Figure 5 is a side view, partly in section and partly in elevation, showing another modified twounittube; and

Figure 6 is a similar view of afour-umt tube. 552

Figure '7 is a horizontal sectional view taken in a plane indicated by line 1-1 of Figure 6. 1 Irrterms o-fbroadinclusion, our electrical discharge device comprises a plurality of units mounted within a Single envelope and each including a plurality of electrodes such as cathode, grid and anode. Improved means are provided for mounting the electrodes of; the several units, and means are provided for establishing connections with the electrodes for operating the units either independently or simultaneously. Another feature of our invention relates to improved means for radiating heat from an electrode such as an anode. Our invention also embodies an improved method of assembling the electrodes in a tube.

In greater detail, andreferring to. Figure l of the drawings, one type of two-unit tube embodying the improvements of our invention comprises an envelope of vitreous material such as glass having an upper end or domeportion 2, an intermediate portion including a-reduced neck 3 and a shoulder 4, and a lower end portion including. a reentrant stem 6. The base of the tube comprises a porcelain collar Tl secured to the neck by cement 8 and carrying four terminals or prongs 9 thre of which are s'hown'in Figure l.

The two units are preferably disposed symmetrically about the axis of the tube; and each comprises a set of "electrodes including a cathode or filament l I, a grid or control electrode 12', and an anode or plate l3. Cathodes II are supported from stem 6 by conductors l4; grids l2 from shoulder 4 of the intermediate tube portion by conductors l5;,and anodes 13 from dome portion 2 by conductors it. These supporting wires are all sealed in the tube portions indicated and provide external connections for the various electrodes. The mounting of the grid supports at shoulder 4 instead of in the base of the tube materially reduces the interelectrode' capacities atthe base.

Cathodes ll may'beof any suitable form, such as the coiled filaments'illustrated; one filament being connected to'one'pair' of terminals 9 by leads IT and the other filament being connected to-th'e' other-pair of terminals by'leads l8. Grids 12 are also of optional construction, the type shown comprising a series of verticalwires with an outerreinforcing'helixall' held by a basering secured to support I5 by an arm 19.

Anodes I3 may be of any desired construction, but better results are secured by using the particular type shown. Our improved anode is hollow and preferably cylindrical in shape, and has aseriesoi say three radiatingfins 29-disposed wider than the others. In other words, the fins are arranged and proportioned to, provide heat} radiating surfaces varying in size in accordance with the degree of heat to be dissipated. The use of annular fins makes this arrangement possible. Annular fins have the further advantage of embracing the full diameter of the electrode,

thereby giving the most effective heat radiation,-

particularly along the mid-diameter where the maximum heating occurs. This arrangement of coolingfins is much superior to the longitudinal fins commonly used, andwe have materially increased the output of our tubes merely by making this change. It is to be understood that these improvements in the anode structure per se are adaptable for use in ordinary single-unit tubes as well as in our multiple-unittubes.

The anodes of the tube type shown in Figure 1 are separately supported by the conductors I6, each anode being fastened to its support by a strap 2| secured to a cap 22 of the electrode. These'supports being separate from and independent of the heat radiating fins tends to thermally isolate the anode; which is desirable for the purpose of keeping the'glass seal at the support from undue heating; Separate external connections can thus be made to each electrode of each unit, so that one unit may beoperated independently of the other. When the units are operated singly the life-of the tube-is doubled, it being only necessary to turn the tube around in the socket to bring another unit into operation when one of the filaments burns out. Another important feature is that the inactive unit may be employed for neutralizing capacity. The two units thereby mutually cooperate in the functioning of the tube, even though only one nut is in actual operation and even thoughthe other unit may be burnt out. If desired, of course, the electrodes having similar function may be connected in parallel to simultaneously operate the units.

For simultaneous operation however the an odes are preferably connected in parallel'to, a common central support 23 as shown in Figures 3 and 4. In this case a bracket is provided with lateral fins 24 embracing the support and with base flanges 26 secured to the upper fins of the anodes. Fins 24 extend upwardly along the sup port and decrease in width therealong. These fins aid in radio frequency conduction, and also function to dissipate heat.

Figure 5 shows another two-unit tube having units adapted for simultaneous operation. The grids are connected in parallel by a conducting ring 21 having a terminal button 28 and secured to the shoulder of the envelope by a suitable cement 3|; the grid conductors being joined to the ring at lips 32.

Figure 5 also shows a variant type of anode mounting employing anodes 33 having ordinary longitudinal fins 34. Fins 36 of thesupporting bracket embrace conductor 31 and lap the inwardly extending fins on the anodezso thatthe 75 four anodes are all connected in parallel to the commonsupport 37, and the four grids are connected in parallel to ring 27. The cathode connections in this tube are made to the four base terminals 9 by connecting two of the filaments in parallel to a pair of terminals by leads 38 and 39, and connecting the remaining two filaments in parallel to the other pair of terminals by leads 4| and 42.

Another feature of our invention, which is applicable to ordinary one-unit tubes as well as .our multiple-unit tubes, relates to a methodof ,assembling the electrode in the envelope to insure accurate alignment and spacing. With reference to the tube type shown in Figure 1, for example, and referring particularly to Figure 2, our method comprises forming the envelope in a plurality of say three separate sections correspondingto the three portions previously referred to herein; namely, an upper end section including dome 2, an intermediate section including neck 3 and shoulder 4, and a lower end section including stem 6. The cathode structure is mounted 'on the stem section, the grid structure on the intermediate section, and the anode structure on the dome section. By this arrangement the several electrode structures may be readily and accurately fabricated on suitable jigs. The envelope sections are then fused together; the lower and intermediate sections being preferably fused first to enable proper alignment of the cathode and grid structures before the dome section is sealed inplace.

V .Our multiple-unit tubes in which the. units operate in unison give excellent results. Many unsuccessful attempts have been made in; the past to produce large tubes having the high operatingefiiciency characterizing tubes of smallphysical size. "In our improved tubcswhere several small operative units are assembled within a single en; velope, the individual units are designed with electrode spacings approximating thev ideal'iin regard to transit time effects, electron fmigra; tion,'in.-terelectrode capacity and thermionic e111; 'ciency. Our tubes'are extremely easy to drive} provide a high power output'at low plate volt age and the' small inter'electrodecapa'citiesn able them to operate effectively at ultra high fr'e quencies. Weclaim: p Q. 1. In an electrical discharge device, an envelope, a. plurality of cathodes and gridsj andlan odes in the envelope, said envelope having an an nular shoulder providing aledge intermediate the ends of the envelope, conductor meanslforjthe cathodes extending through an end 10f. the Lenve lope, conductormeans for the anodes' exte'nding through the other end'of the envelope; and con ductor means for the grids extending through said ledge.

2. In an electrical discharge-devicefah enve lope, a plurality of anodes disposed about sub: stantially parallel axes in the envelope,'ja grid and cathode associated with each anode;'said en velope' having a reentrant stem atone end-therehaving an envelope :enclosing a plurality of cathodes and grids and anodes, which comprises forming the envelope in a plurality of sections,

including intermediate and two end sections, mounting the cathodes on one end section, mounting the grids on the intermediate section, mounting the anodes on the other end section, and uniting the sections of said envelope.

4; An electronic tube comprising an envelope having a stem at one end thereof, a plurality of anodes and associated grids and cathodes in the envelope, an anode lead sealed to the end of the envelope opposite said stem, means for unitarily supporting the anodes on said lead, conductor means for the grids sealed to the envelope portions intermediate the anode lead and said stem, and conductor means for the cathodes sealed in the stem, said conductor means for said cathodes being joined to connect the cathodes in parallel.

5. An electronic tube comprising a sectional vitreous envelope having a reentrant stem in the lower section thereof, a plurality of tubular anodes in the envelope, conductor means connected to the anodes and sealed to and supported by the upper section of the envelope, a grid associated with each anode andhaving an upper free end and a lower terminal end, conductor means connected to the terminal ends of the grids and sealed to intermediate portions of the envelope, a cathode associated with each anode, and conductor means connected to the cathodes and sealed in said stem.

6. An electronic tube comprising a vitreous envelope having a reentrant stem at the lower end and having an annular shoulder intermediate its ends, a plurality of tubular anodes spaced about the axis of the envelope, conductor means connected to the anodes and sealed to the upper portions of the envelope, a grid associated with each anode, conductor means connected to the grids and sealed to the envelope adjacent said shoulder, a cathode associated with each anode, and conductor means connected to the cathodes and sealed to said stem.

7 An electronic tube comprising a vitreous envelope having a reentrant stem at the lower end and having an annular shoulder intermediate its ends, a plurality of tubular anodes spaced about the axis of the envelope, conductor means connected to the anodes and sealed to the upper portions of the envelope, a grid associated with each anode, a plurality of leads each connected to one of the grids and disposed in a circle with their ends sealed to the envelope adjacent said-shoulder, a cathode associated with each anode, and

*c 'onductor means connected to the cathodes and sealed to said stem.

8. An electronic tube comprising a vitreous envelope having portions fused together along a plane intermediate the ends of the envelope, a tubular anode within but distinct from said envelope, a grid and cathode extending within said anode, means supporting the anode on one of the envelope portions, and means supporting the grid and cathode on the other portion.

9. An electronic tube comprising a sectional envelope, a plurality of tubular anodes in the envelope, a seal joining the envelope sections in a plane transverse to the axes of said anodes, conductor means connected to the anodes and sealed to and supported by a section of the envelope lying at one side of said plane, a cathode extending within each anode, and conductor means connected to the cathodes and sealed to and supported by a section of the envelope lying at the opposite side of said plane.

WILLIAM W. EI'I'EL. JACK A. McCULLOUGH. 

